Time-Reversal signal processing: An overview

Abstract

The development of time reversal (T/R) techniques both theoretically and pragmatically has heightened in interest over the last decade. Although the majority of the effort has been concentrated in analysis and proof-in-principle experiments, the evolution of these results have led to potential applications in signal processing. These range from the detection of flaws in nondestructive evaluation (NDE) and scatterers in ocean acoustics to the destruction of kidney stones in biomedical ultrasound. When the medium under investigation has quasihomogenous properties, imaging using the T/R operator has evolved as a viable entity. In this paper we present an overview of T/R from a signal processing perspective. Here we concentrate on the ability of the T/R to perform its primary function of ‘‘focusing’’ on the strongest scatterer. We show how the T/R properties provides us with the optimal spatio-temporal matched-filter property which is utilized in a wide variety of applications, especially in NDE, biomedical, and the newly investigated communications area. We note the relationship of T/R to the inverse solution providing an alternative in deconvolution-type problems.